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HANDBOOK OF PHYSIOLOGY. 



endothelium on its pleural and peritoneal surfaces, and its substance 

 consists of tendon bundles arranged in concentric rings towards the 

 pleural side and in radiating bundles towards the peritoneal side. 



The lymphatics of the anterior half of the diaphragm open into 

 those of the anterior mediastinum, while those of the posterior half pass 

 into a lymphatic vessel in the posterior mediastinum, which soon enters 

 the thoracic duct. Both these sets of vessels, and the glands into which 

 they pass, are readily injected by the method above described; and there 



Fio. 217. 



FIG. 218. 



FIG. 217. Superficial lymphatics of the forearm and palm of the hand, 1/5. 5. Two small 

 glands at the bend of the arm. 6. Radial lymphatic vessels. 7. Ulnar lymphatic vessels. 8, 8. Palmar 

 arch of lymphatics. 9, 9'. Outer and inner sets of vessels. 6. Cephalic vein. d. Radial vein. e. 

 Median vein. /, Ulnar vein. The lymphatics are represented as lying on the deep fascia. (Mascagni.; 



FIG. 218. Superficial lymphatics of right groin and upper part of thigh, 1/6. 1. Upper inguinal 

 ands. 2, 2'. Lower inguinal or femoral glands. 3, 3'. Plexus of lymphatics in the course of the 



glan 

 long 



saphenous vein. (Mascagni.) 



can be little doubt that during life the flow of lymph along these chan- 

 nels is chiefly caused by the action of the diaphragm during respiration. 

 As it descends in inspiration, the spaces between the radiating tendon 



